Experiments

FG

A B

G

T

DC Voltm

0.007m V

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AC Voltm

7.0717 V

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Oscil.

University Of Jordan

Faculty of Engineering

Electrical Engineering Department

Electronics Lab

• Eng. Sanaa Al- Khawaldeh

• Eng. Noor Awad

0903368

Prepared by

1 University of Jordan Electrical Engineering Department

Exp No. Experiment Page

1 Lab Equipment Familiarization 3

2 Diode Characteristics & Rectifications 8

3 Diode Clippers & Clampers 13

4 Zener Diode Characteristics & Voltage Regulator 18

5 Bipolar Junction Transistor Characteristics 23

6 BJT ac Amplifier & Switch 28

7 Metal Oxide Semiconductor Field Effect Transistor 33

8 BJT Frequency Response Amplifiers 39

9 Operational Amplifier Application 42

10 Project Design

11 Appendix


Theory

• Oscilloscope

Using an Oscilloscope can be easy! The less you ask from it, the easier it is to use.

Work in any circuits & electronics lab relies heavily on the use of the digital multi-

meter (DMM), the Oscilloscope, and the Function Generator. You have already

gained some experience with the DMM; in this experiment we want you to become

familiar with the Oscilloscope.

The Oscilloscope is simply the most useful instrument available for testing circuits

because it allows you to see (observe) the signals at different points in the circuit. The

best way of investigating an electronic system is to monitor signals at the input and

output of each system block, checking that each block is operating as expected and is

correctly linked to the next. With a little practice, you will be able to find and correct

faults quickly and accurately. Also it can be employed to measure voltage, frequency

and phase shift. Many other quantities such as pulse width, rise time, fall time and

delay time can be investigated.

The function of an Oscilloscope is very simple. It draws a

V/t graph, a graph of voltage against time, voltage on the

vertical or Y-axis, and time on the horizontal or X-axis. As

you can see in Figure 1, the screen of an Oscilloscope

almost has 8 squares/divisions on the vertical axis, and 10

squares/divisions on the horizontal axis. Usually, these

squares are 1 cm in each direction.

The Oscilloscope has extremely high input impedance (1 M, parallel with 25 pF),

which means it will not significantly affect the input signal. This is nice because you

can use it to test a circuit without having to worry about it causing the circuit to

behave differently. The probes are connected to an Oscilloscope using BNC’s( Baby

N- Connector).

An Oscilloscope can be separated into four major sections: 1- Display, 2- Vertical,

3- Horizontal and 4- Triggering sections. Table 1 summarized these sections.


Lab Equipment Familiarization

Exp. 1

Objectives

• To be familiar with the main blocks of the oscilloscope and the function of each block.

• Understand how an oscilloscope works, and how to use the various controls .

• Generate and explore different waveforms that are commonly used. • Compute and measure Vp-p, Vp, Vavg, and Vrms.

• Measure the period and frequency of periodic ac signals.

Figure 1

Table 1

Display

Section

Controls the graph on the CRT.

POWER Turns ac mains on and off.

INTENSITY Adjusts the brightness of the trace.

FOCUS Adjusts the sharpness of the trace.

Vertical

Section

Supplies the information for the Y-axis (or vertical axis). Usually the scope has two

channels. This means two signals can be viewed at once.

VOLTS/DIV Vertical sensitivity controls the number of volts between each

horizontal line on the screen.

POSITION

Allows you to move the trace up or down as you see it fit. This way

you can zero the trace when no voltage is applied, or if you are

viewing two waves at once you can separate them.

VERT MODE

Channel 1/A: shows only channel 1’s signal.

Channel 2/B: shows only channel 2’s signal.

Dual: shows both signals at once.

Add: Algebraically adds channel 1 to channel 2.

VAR Variable: allows you to adjust the calibration of the signal. Be sure

this is locked in the CAL position.

AC/GND/DC

Called coupling switch.

AC coupling: the scope will display the AC component; block any

DC component from being displayed.

DC coupling: the scope will display the complete signal including

the DC component.

GND: Disconnects the input signal from the system so you can

establish a zero line.

Horizontal

Section

The horizontal axis on a scope changes with respect to time.

POSITION Allows you to adjust the wave to the left or right.

TIME/DIV

Controls the rate at which the trace travels between divisions. Set it

to one second and the trace will take a second to travel between one

division and the next.

X10 MAG Multiplies the time trace by 10.

X – Y This cause the scope to graph channel 1/A on the x-axis and channel

2/B on the Y-axis.

SWP VAR When in, you can vary the time base away from the Time/Div dial.

Be sure this is locked in the CAL position.

Triggering

Section

This tells the scope when to trigger or start the beginning of a trace. Helps it to

"lock-on" to the trace.

LEVEL Allows the user to vary the waveform in order to synchronize the

start of the wave.

HOLD OFF Allows fine tuning of the Level. Useful when a trace is tough to

lock-on to.

AUTO Automatically operates trigger on its own action.

COUPLING Usually set to AC for this lab.

SOURCE Set to Channel 1/A or Channel 2/B. Which ever works better.

SLOPE + - Flips the waveform on both channels by determining whether the

slope triggers on the positive or the negative slope.


• Coaxial Cables

The cables you are using to connect the FG and the Scope,

are called coaxial cables, and they contain two coaxial

conductors with characteristic impedance of 50 . The center

or inner (High) conductor carries the signal and the outer

conductor is typically connected to ground (Low) at one or

both ends of the cable. Figure 2 shows a cross section of a

coaxial cable. Properly grounded coaxial cables are reducing

or prevent the noise and interference signals.

Outer insulation Outer conductor Inner insulation

Inner conductor

Figure 2

• Function Generator

The Function Generator can produce periodic signals of varying frequency, amplitude

and several different shapes including: Sine, Square and Triangular signals,

TTL/CMOS digital pulses, …etc. Both frequency and amplitude can be varied.

Procedure

PART A – Using Oscilloscope and Function Generator

1- Turn on the Oscilloscope, choose CH1 from the Vertical

Mode (to display only channel 1 signal). Set the

Oscilloscope’s “Volts/Division” knob for “channel 1” to

2V/DIV, and set the sweep “Seconds/Division” knob to

0.2 ms/DIV.

2- Set the coupling switch (AC/DC/GND) to GND and move

the trace to the middle of the screen. When you finish set

the coupling switch to AC again.

3- Turn on the Function Generator and connect the output of

it to the input of CH1 of the Oscilloscope.

4- While observing the signal on the Oscilloscope, turn the amplitude potentiometer

knob and the frequency knob of the Function Generator to get 8Vpp, 1kHz on the

Oscilloscope screen.

5- Draw the signal displayed on the Oscilloscope screen.

6- Turn the “Volts/Division” knob for channel 1 in the CW and then CCW directions.

How does that affect what you see on the Oscilloscope?

Equipments & Part List

1- Oscilloscope. 2- Function Generator (FG) or Signal Generator.

3- Digital Multimeter (DMM). 4- Bread-board.

6- Connection Wires and coaxial cable Probes.


Note

Be sure that the VAR knob of the “Volt/Division” and “Second/Division” is locked in the

CAL (Calibration) position, so don’t change it.

Note

DMM can be used as continuity tester to check the connection between the grounding pin

(on the line plug) and the metal parts of the Oscilloscope, especially with BNC connectors

and grounding jack. All metal parts of the Oscilloscope case connected to the building

ground when is Oscilloscope plugged in, which is for safety purposes

Note

Practically DMM’s are used to measure the Effective Voltage (Vrms) and the average

Voltage ( Vavg). Such that:

Vrms = VAC (only for pure sine wave)

Vavg = VDC

7- Turn the “Seconds/Division” knob for channel 1 in the CW and then CCW

directions. How does that affect what you see on the Oscilloscope?

8- Turn the “Intensity” knob for channel 1 in the CW and then CCW directions. How

does that affect what you see on the Oscilloscope?

9- Turn the “Focus” knob for channel 1 in the CW and then CCW directions. How

does that affect what you see on the Oscilloscope?

10- Turn the “Vertical Position” knob for channel 1 in the CW and then CCW

directions. And turn the “Horizontal Position” knob in the CW and then CCW

directions. What are the affects of these knobs on the signal?

11- Turn the “Level” knob in the CW and then CCW directions. What is the affect of

this knob on the signal?

12- Set the “Triggering Source” knob to CH2 ( EXT in other types of Oscilloscope).

What happen to the signal? Explain. (When you finish set it back to CH1).

14- How many screen divisions of the Oscilloscope:

1) Horizontally: . . . . . . . . . . .

2) Vertically: . . . . . . . . . . . . .

3) Subdivisions: . . . . . . . . . .

PART B - Measuring Time , Frequency and Amplitude

1- Connect the output of a Function Generator to the CH1 input on the Oscilloscope.

2- Set the sine waveforms listed in Table 1, using the Oscilloscope and DMM to

complete the rest of the table.

3- Sketch the waveforms on the respective screen grid provided. Record the HORZ.

and VERT. settings.


Freq. and Amplitude Vrms (V) Vavg (V)

f = 500 Hz @ 800 mV pp

f = 10 kHz @ 10Vpp

4- For a sine wave of 250 kHz, what is the “Second/Division” needed to display 2.5

cycle on the Oscilloscope screen?


Table 1

Objectives

• To be familiar with the basic properties of the junction diodes.

• To study the characteristics of the diode and investigate the I-V curve.

• To investigate the concept of rectification properities.

Pre-Lab Assignments

Build the circuits in the experiment by using the MultiSIM simulation packages, to

obtain the expected results and graphs.

Theory

The diode is a two-terminal semiconductor device with

a nonlinear i-v characteristic. The current flows in only

one direction through the diode from the anode to the

cathode. There are three operating regions for the diode:

• Forward biased.

• Reverse biased.

• Reverse breakdown.

From examining Figure 1, you should note that the Anode (A) corresponds to the P-

type side while the Cathode (K) corresponds to the N-type side of the diode.

The purpose of rectifier circuits is to convert AC voltage to DC voltage. That is, the

current flows through a load in one direction only, positive or negative with respect

to common (0V or GND) point).

This DC level is the average of the peak load voltage (VP) over a complete period

(360 or (2)) which can be expressed for rectified unfiltered sinusoidal signals as a

constant and equals to:

- Vav = VDC = VP/ = (0.318)VP (for half-wave rectification).

- Vav = VDC = 2VP/ = (0.636)VP (for full-wave rectification).

The frequency of the rectified output waveform can be expressed as:

- fO = fSource (half-wave rectification).

- fO = 2fSource (full-wave rectification).

The percentage ripple can be expressed as:

- Percentage Ripple = ( Vr-PP / Vav )* 100%.

The purpose of the filter capacitor is to reduce the amount of ripple voltage at the

output of the rectifier circuit. The capacitor charges to approximately the peak voltage


Diode Characteristics & Rectifications

Exp. 2


1- Oscilloscope. 2- Function Generator (FG) or Signal Generator.

3- Digital Multimeters (DMM). 4- DC power supply.

5- Project Breadboard. 6- Resistors of 100, 1K, 10K, 100K.

7- Capacitors of 1µF and 2.2µF. 8- Diode 1N4006 and Bridge rectifier.

9- Connection Wires and coaxial cables probes.

across the load voltage VL-P and then discharges through the load resistance RL as the

rectified DC falls below VP .

As long as the discharge time for the capacitor is greater than the time between the

peaks of the rectified DC, the load voltage can be found using the formula shown.

Vav = VL-P - (Vr-PP /2)

Procedure

PART-A Diode (I-V) characteristics

A-1 Diode Testing:

1- Insert the two leads of the Diode 1N4006 to the breadboard.

2- Turn on the DMM and configure it to diode test . Plug a black test lead into the

Common (−) banana socket and a red test lead into the V (+) banana socket

of the DMM.

3- Put the leads (black and red) to both terminals of the diode, and then check the

DMM reading.

4- Determine if the diode is working well or not. Explain briefly.

A-2 Forward Bias Mode

1- Construct the circuit shown in Figure 2. By using 1N4006 Si

diode. (Make sure your diode has the correct polarity).

2- Ask the instructor to check your circuit.

3- Set the DC power supply output adjustment potentiometer fully

counter clock wise. Then switch it ON.

4- Adjust the voltage source (VS) corresponding to Table 1. Use the

DMM to measure the remaining values and record it in Table 1.

5- When finish, set the (VS) to 0.0V. Then switch OFF the DC power supply.

A-3 Reverse Bias Mode

1- Reverse the polarity of the DC power source (VS) as shown in Figure 3.

2- Adjust the voltage source (VS) corresponding to Table 2. Use the DMM to measure

the remaining values and record it in Table 2.

3- When you finished, set the (VS) to 0.0V. Then switch OFF the DC power supply.

VS (V) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.6

ID (mA)

VD (V)

Table 1


D 1N4001

RL 1K

VS

10 VPP 100 Hz

Ch2 Ch1

H-1

L-1

H H-2

L L-2

FG

D 1N4001

RL 1K

VS

10 VPP 100 Hz

Ch2 Ch1

H-1

L-1

H H-2

L L-2

FG

Table 2

4- Using the data obtained in part A-2 and part A-3 above, plot the diode (I-V)

characteristic curve, and answers the followings:

1) Determine the small signal conductance (g) of the diode at the bias point

calculated in the previous step. (g is the slope at the bias point).

2) Suggest a piece-wise linear model for the used diode and draw it on the I-V

graph.

3) Sketch the corresponding equivalent circuit of the diode.

PART-B Rectification

B-1 Unfiltered Half-wave Rectifier

1- Construct the circuit shown in Figure 4.a by using 1N4006 Si diode.

2- Switch ON the Oscilloscope.

3- Switch ON the Function Generator and set the source voltage (VS) to 10Vp-p,

100Hz, sinusoidal.

4- Use the Oscilloscope to measure and record VLoad-P from Ch2. Sketch the

Oscilloscope screen on the respective grids in Table 3.

5- Reverse the diode according to Figure 4.b and repeat step 4.

6- What about the Frequency of the Output Signal.

Table 3

VS (V) 2.0 5.0 10.0 15.0

ID (mA)

VD (V)

Circuit VS & VL waveforms

Figure 4.a

Figure 4.b

University of Jordan Electrical Engineering Department 10

B-2 Filtered Half-wave Rectifier

1- Construct the circuit shown in Figure 5.

2- Use the value of Capacitor C and Load resistor RL

according to Table 4. (Be sure to observe the

capacitor polarity).

3- Use the Oscilloscope to measure the Ripple Voltage Vr-pp (since Vr-pp = Vout-pp) from Ch2, use DMM to measure

the Average Voltage ( Vavg ). Calculate Ripple Percentage ( Ripp.%)and sketch the

Oscilloscope screen on the respective grids in Table 4.

4- Repeat the steps 2 to 3.

5- Switch OFF the Function Generator

Table 4

B-3 Full-wave Bridge Rectifier

1- Construct the circuit shown in Figure 6 by using

the Bridge rectifier chip. (Be sure to observe the

capacitor polarity).

2- Switch ON the Function Generator and set the

source voltage (VS) to 10Vp-p, 100Hz, sinusoidal.

3- Use the Oscilloscope to measure and record the Vr-pp from CH2 only while CH1 is disconnected (

Why? ). Sketch the Oscilloscope screen on the

respective grids in Table 5.

4- Replace the components of RL and C according to Table 5.

5- Repeat the steps 3 to 4.

VS & VL waveforms Vr-PP (V) Vavg (V) Ripp.% VS & VL waveforms

RL = 1 kΩ. C = 1 µF.

RL = 10 kΩ. C = 1 µF.

RL = 10 kΩ. C = 2.2 µF.

RL = 100 kΩ. C = 2.2 µF.


Figure 5

Figure 6

Table 5

6- On the same circuit shown in Figure 6 by using RL = 1 kΩ, and C = 1.0 µF.

Observe the effect of increasing signal frequency to 1 kHz on the ripple

voltage. Explain. 7- How many ways to control the ripple voltage? Mention.

8- What about the Frequency of the Output Signal?

9- Switch of the Function Generator.

VL waveform Vr-PP (V) Vavg (V) Ripp.% VL waveform

RL = 1 kΩ. without capacitor

RL = 1 kΩ. C = 2.2 µF.

RL = 10 kΩ. C = 2.2 µF.

RL = 100 kΩ. C = 2.2 µF.


Objective

To investigate the diodes applications in clipping and clamping circuits.

Note

• To observe signal on the Oscilloscope screen, put the Channel coupling is set to DC

not AC.

Pre-Lab Assignments

Build the circuits in the experiment by using the MultiSIM simulation packages, to

obtain the expected results and graphs.

Theory

Clipping and Clamping circuits are circuits that shape or modify an ac waveform.

Diode clipper circuits are also called limiters. They limit or clip off the positive (or

negative) part of an input signal. Clipper circuits are concerned primarily with

limiting or cutting off part of the waveform, due to that they can be used for circuit

protection or waveform shaping.

Diode Clampers add or shift a dc level to an ac signal, and are sometimes known as dc

restorers. For example, if we have a clock signal that swings between 0V and 5V but

our application requires a clock signal from -5V to 0V, we can provide the proper DC

offset by using a passive Clamper circuit. For the clamping circuit to work properly

the pulse width should be less than the RC time constant () of the circuit, by a factor

of 5 approximately. Because of the time constant requirement the voltage across the

capacitor can not change significantly during the pulse width, and after a short

transient period the voltage across the capacitor reaches a steady state offset value.

The output voltage is simply the input voltage shifted by this steady state offset. Also,

observe that the peak-to-peak output voltage is equal to the peak-to-peak input

voltage. Because the voltage across the capacitor can not change instantaneously and

the full change of voltage on the input side of the capacitor will likewise be seen on

the output side of the capacitor.

Diode Clippers & Clampers

Exp. 3


2


1- Oscilloscope 2- Function Generator (FG) .

3- Two Digital Multimeters (DMM). 4- DC power supply.

5- Project Breadboard. 6- Resistors of 1K and 100K.

7- Capacitors of 1µF. 8- Diode 1N4006.

9- Connection Wires and coaxial probes.

Procedure

PART-A Diode Clipper circuits

A-1 Positive Clipper

1- Construct the circuit shown in Figure 1.a by using 1N4006 Si diode.

2- Switch ON the Oscilloscope.

3- Switch ON the Function Generator and set the source voltage (VS) to 8Vp-p, 100Hz,

sinusoidal.

4- Use the Oscilloscope to measure and record the VS from CH1 and VO from CH2.

Sketch the Oscilloscope screen on the respective grids in Table 1. (Note: set the

input coupling switch of the Oscilloscope to the DC coupling mode).

5- Switch OFF the Function Generator, and insert the DC power supply as shown in

Figure 1.b.

6- Switch ON the DC power supply and the Function Generator, and set the DC

voltage to 2V. Then repeat step 4.

7- When finished, switch OFF the DC power supply and the Function Generator.

Table 1

Positive clipper data of Figure 1.a Positive clipper data of Figure 1.b

VO-min = …………. VO-max = …………..

VO-min = …………. VO-max = …………


Figure 1.a Figure 1.b

8- If you want to draw the resistor voltage waveform

(Rectified Signal):

a) What are the changes you had to do in the circuit shown

in Figure 1.a?

b) Draw the circuit again and show the locations of the

Oscilloscope channels terminals. Explain.

c) Sketch the output waveform in this case.

A-2 Negative Clipper

1- Construct the circuit shown in Figure 2.a by reversing the diode of the previous

circuit.




3- Switch OFF the Function Generator, and insert the DC power supply as shown in

Figure 2.b.

4- Switch ON the DC power supply and the Function Generator, and set the DC

voltage to 2V. Then repeat step 2.


6- Explain the effects of using a diode that is not ideal.

Table 2

Negative clipper data of Figure 2.a Negative clipper data of Figure 2.b

VO-min = …………. VO-max = …………..

VO-min = …………. VO-max = …………


Figure 2.a Figure 2.b

PART-B Diode Clamper circuits

B1- Positive Clamper





3- When finished, switch OFF the Function Generator.

4- What happen when using clamping circuit to drive low load impedance? Does the

circuit still work as clamper? Explain.

Table 3

Positive clamper data of Figure 3 Positive clamper capacitor waveform

VO-min = …………. V O-max =………….

Vr-pp = ………….

B-2 Negative Clamper



Sketch the Oscilloscope screen on the respective grids in Table 4.

3- When finished, switch OFF the instruments and ask the instructor to disconnect the

circuit.


Figure 3

Figure 4

Table4

Negative clamper data of Figure 4 Negative clamper capacitor waveform

VO-min = …………. VO-max =………….. Vr-pp = ……….


Figure 1

Objectives

To be familiar with the reverse Zener Diode Characteristic and the application of the

Zener diode as Voltage regulation.

Pre-Lab Assignments

Pre1. What is the difference between a Zener diode and a “standard” rectifier diode?

Pre2. Build the circuits in the experiment by using the MultiSIM simulation

packages, to obtain the expected results.

Theory

The Zener diode operates in the reverse breakdown region as

shown in Figure 1. The Zener diode has almost a constant

voltage across it as long as the Zener diode current is between

the knee current IZK and the maximum current rating IZM.

Voltage Regulator, a voltage regulator circuit is required to

maintain a constant dc output voltage across the load terminals in

spite of the variation:

• Variation in input mains voltage (Vs).

• Change in the load current (IL)

The voltage regulator circuit can be designed using zener diode.

For that purpose, zener diode is operated always in reverse biased condition. Here,

zener is operated in break down region and is used to regulate the voltage across a

load when there are variations in the supply voltage or load current.

Figure 2 shows the zener voltage regulator, it consists of a current limiting resistor RS

connected in series with the input voltage Vs and zener diode is connected in parallel

with the load RL in reverse biased condition. The output voltage is always selected

with a breakdown voltage Vz of the diode.

The input source current:

IS = IZ + IL………….. (1)

The drop across the series resistance:

VRs = VS – Vz …….. (2)

And current flowing through it:

Is = (Vs– VZ) / RS ………….. (3)

From equation (1) and (2), we get:

(Vs - Vz ) / Rs = Iz +IL ………… (4)

Zener Diode Characteristics & Voltage Regulator

Exp. 4



1- Oscilloscope 2- Function Generator (FG) .


5- Project Breadboard. 6- Resistors of 100, 220, 1K and 10K.

7- Zener diode 5V. 8- Connection Wires and coaxial cables.

Regulation with a varying input voltage (line regulation): It is defined as the

change in regulated voltage with respect to variation in line (input) voltage.

In this, input voltage varies but load resistance (RL) remains constant hence, the load

current remains constant. As the input voltage increases, form equation (3) Is also

varies accordingly. Therefore, zener current Iz will increase. The extra voltage is

dropped across the Rs. Since, increased Iz will still have a constant Vz and Vz is

equal to Vout. The output voltage will remain constant.

If there is decrease in Vs, Iz decreases as load current remains constant and voltage

drop across Rs is reduced. But even though Iz may change, Vz remains constant

hence, output voltage remains constant.

Regulation with the varying load (load regulation): It is defined as change in load

voltage with respect to variations in load current. To calculate this regulation, input

voltage is constant and output voltage varies due to change in the load resistance

value. Consider output voltage is increased due to increasing in the load current. The

left side of the equation (4) is constant as input voltage Vs, IS and Rs is constant.

Then as load current changes, the zener current Iz will also change but in opposite

way such that the sum of Iz and IL will remain constant. Thus, the load current

increases, the zener current decreases and sum remain constant. From reverse bias

characteristics even Iz changes, Vz remains same hence, and output voltage remains

fairly constant.

Zener diode MUST be operated under load. If not, the Zener may burn.

Procedure

PART-A Zener Diode Characteristics

1- Construct the circuit shown in Figure 2. By

using Si Zener diode. (Make sure the diode is

connected with the correct polarity).

2- Set the DC power supply output adjustment

potentiometer fully counter clock wise, then

switch it ON.

3- Adjust the voltage source (VS) corresponding

to Table 1. Use the DMM to measure the

remaining values and record it in Table 1.

(Do not exceed the Zener (reverse) current

of 20 mA).

4- When finished, set the (VS) to 0.0V. Then switch OFF the DC power supply.


Figure 2

Note

You had to know that VD = - VO and IZ = - Is

Figure 3

Table 1

VS (V) 1.0 2.0 4.0 5.0 5.2 5.5 6.0 6.5 7.0 8.0 9.0

ID (mA)

VD (V)

6- Plot the reverse diode current vs. the reverse diode voltage (voltage on horizontal

axis) on Figure 3. Label each axis with suitable units.

7- From the curve you draw in question 6, determine the Zener breakdown voltage

VZK.

8- Calculate the Zener diode dynamic resistance rZ, where:

rZ = VD / IZ ( for |VZK| < |VD| < |VZM| ).

PART-B Zener Diode Voltage Regulator

B-1 Effect of the DC Voltage source on the Zener regulator

1- Construct the circuit shown in Figure 4. By using Si Zener diode. (Make sure the

diode is connected with the correct

polarity).

2- Set the DC power supply output

adjustment potentiometer fully counter

clock wise. Then switch it ON.

3- Adjust the voltage source (VS)

corresponding to Table 2. Use the

DMM to measure the load voltage VO,

IS and record it in Table2. Then

Calculate IL , IZ and PZ Where:

IL = VO / RL , IZ = IS – IL and PZ = IZ x VZ .

4- When finished, set the (VS) to 0.0V.


Figure 4

Table 2

VS (V) 1.0 2.0 4.0 5.0 6.0 7.0 8.0 9.0

VO (V)

IS (mA)

IL (mA)

IZ (mA)

PZ (mW)

V.R %

6- Explain what happens to VO and why.

7- Calculate the value of VSmin in Figure 4 for which the Zener diode will no longer

provide voltage regulation. Verify your calculation experimentally (Assume that

the minimum Zener diode current IZmin = 1 mA).

8- Calculate the value of VSmax in Figure 4, for which the Zener diode will reach the

maximum power dissipation, (Assume that the maximum Zener diode current

IZmax = 25 mA).

9- Calculate the percentage voltage regulation (V.R %) of your circuit, and record it

in Table 2. Use the following equation:

V.R % = (( Vno load – Vfull load ) / Vfull load ) x 100%

10- Calculate the value of the series resistor RS-min in Figure 4, at VS = 10V and

RL = 1 K. (Assume that IZmax = 25 mA and IZmin = 1 mA).

B-2 Effect of the Load Resistance on the Zener regulator

1- Set the DC power source (VS) to 10.0V as shown in Figure 5.

2- Use the DMM to measure the load voltage VO and IS and record it in Table 3.

Then Calculate IL, IZ, PZ and V.R %.

3- Replace the load resistance RL corresponding to Table 3. Then repeat step 2 above.

4- When finished, set the (VS) to 0.0V, then switch OFF the DC power supply and

disconnect the circuit.

Table 3

RL (V) 10K 1K 220 100

VO (V)

IS (mA)

IL (mA)

IZ (mA)

PZ (mW)

V.R %

RL-min=


Figure 5

5- Calculate the value of RLmin in Figure 5, for which the Zener diode will no longer

provide voltage regulation. Verify your calculation experimentally.

(Assume the minimum Zener diode current IZmin = 1 mA).

6- Explain why the Zener diode stops regulating for certain values of RL.

7- Calculate the value of the series resistor RS-min in Figure 5, at no load (RL = ).

Assume that the maximum Zener diode current IZmax = 25 mA

B-3 Effect of the AC Voltage Source on the Zener regulator

1- Construct the circuit shown in Figure 6. By using Si Zener diode. (Make sure the

diode is connected with the correct polarity).

2- Set the Function Generator output to 10Vp-p, 1kHz sine wave.


Sketch the Oscilloscope screen on the grid.

4- When finished, set the (VS) to 0.0V.


Figure 6

Objectives

To identify the leads of the Bipolar Junction Transistors (BJT) by using the DMM.

To investigate the DC behavior, analyze and design a DC bias circuit, its operating

point, and the characteristics of a BJT in several regions of operation.

Pre-Lab Assignments

Pre1. By using the data sheet of the BC107 transistor, look up to the following:

o Pin out configuration package (Bottom View)

o Minimum hFE () __________ .

o Maximum hFE () __________ .

o VCE (max) _____________ V .

o IC (max) _____________ V .

o Total maximum power dissipation ______________________ mW .

o Semiconductor material and the type of transistor ___________________

o The complementary transistor of the BC107 is _____________________

Pre2. What is the difference between a BC107 BJT and its complementary transistor;

use the data sheets to determine the differences.

Pre3. Build the circuits in the experiment by using the MultiSIM simulation packages,

to obtain the expected results and graphs.

Theory

A Bipolar Transistor essentially consists of a pair of PN-Junction diodes that are

joined back-to-back. They are found everywhere and used in many electronic circuit

applications such as in sensors, amplifiers, OP-AMPs, oscillators and digital logic

gates. The PC computer contains around a hundred million transistors; or more!.

There are all sorts, shapes, and sizes of transistor. In this lab we will only consider

one basic general purpose type, the bipolar junction transistor. This comes in two

constructions called PNP and NPN. For the following experiments you should use the

BC107 Si, NPN transistors which are available. The BC107 is built into a standard

TO-18 package with three leads. Figure 1 below shows what the package looks like

and identifies the leads.

Bipolar Junction Transistor Characteristics

Exp. 5




3- Project Breadboard. 4- Resistors of 1K and 100K.

5- Connection Wires. 6- BC107 transistor or equivalent.

Figure 1

The DMMs in the lab have a separate function for PN-junction testing. In diode test,

the DMM outputs a constant current of about 1 mA and it measures the voltage

between the two leads without computing a resistance. The measured voltage is the

threshold voltage (V, i.e. (0.5 - 0.65) V for Si, typically less than the normal drop of

0.7 V) of the PN-junction for a 1 mA current, if the PN-junction is forward biased. If

the PN-junction is reverse biased, then the DMM cannot force 1 mA of current into

the PN-junction and the voltage across the PN-junction rises up to the upper range

limit of the DMM, usually about (1.5 to 3.0) Volts. Some meters give an over-limit

(.OL, 1., or 2 to 3V) indication in this case. Using the diode function of a DMM is

another way to perform the above tests, and it gives more understandable information

about the typical PN-junction voltages of the BJT.

The operation of the BJT transistors is very strongly affected by heat, which is usually

internally generated due to power dissipation. It is advisable, therefore, to limit

transistor heating in this experiment by starting data runs with maximum current and

voltage, when the transistor is still cool, and then progressively reducing the current.

(Note: Transistor currents change due to heating effects even when supply voltages

are kept constant).

Procedure

Part-A BJT Lead Identifications by using the DMM

1- Insert the three leads of the BC107 BJT to the breadboard sockets.

2- Turn on the DMM and configure it to measure . Plug a black test lead into the

Common (−) 4mm banana socket, and a red test lead into the V (+) 4mm

banana socket of the DMM.

3- Randomly, label the leads of the transistor as x, y, z.


Figure 2

Note

You had to know that VBE > VBC so we can distinguish between Collector and Emitter

4- Use the DMM according to Table 1 to determine which lead of the BJT is the base

(B) and identify it, and whether the BJT is an NPN or PNP device. Record the

results in Table 1.

5- With the base (B) lead identified, the remaining leads must be the emitter (E) and

collector (C). Try to identify them depends on the obtained measurements; record

the deductions in Table 1.

6- Sketch a bottom view drawing of the device package and label the leads

appropriately as base (B), collector (C) and emitter (E).

Part-B Current-Voltage Characteristics of a CE BJT

1- Construct the circuit shown in Figure 2. By using the BC107 BJT. (Make sure the

transistor is connected with the correct polarity).

2- Set the DC power supplies output adjustment potentiometers fully CCW, then

switch the supplies ON.

3- Adjust the DC power supply of VCC according to Table 2.

4- Adjust the DC power supply VBB to obtain the approximate values according to

Table 2.

5- Use the voltmeter to measure VBE, VCE and IC and calculate IB and, and record

the readings in Table 2.

6- Repeat steps 4 and 5 for all values of VRB.

7- Repeat steps 3 to 6.

8- When finished, set the VBB and VCC to 0.0V. Then switch OFF the DC power

supplies.

DMM leads + x, - y + x, - z - x, + y - x, + z + y, - z - y, + z

test (V)

From the measurements above, summarize the type and terminals of the given BJT

Transistor type Base (B) Collector (C) Emitter (E)


Table 1

Note

The average βDC (hFE) you calculated here can be used in the next experiment to make

a design for an amplifier.

9- From your data in Table 2, plot the experimental output collector characteristics (IC

vs. VCE) at VBB= 4volt, draw the load line on the same graph, determine the Q-

point (Operating Point) and determine the 4 regions of operations.

10- From your data in Table 2, plot the input characteristics (IB vs. VBE) at VCC= 15V.

11- From the experimental results calculate the average DC (hFE). For what

significant reasons is the experimental different from the manufacturer's

specified value?

12- From the above , calculate the corresponding alpha .

13- On the basis of the measurements you made, what material is the transistor made

of? How did you arrive at this conclusion?

14- Explain how the Common Emitter (CE) characteristics would be different if

were increased?


Note

* IB = ( VBB – VBE) / RB

* βDC = IC / IB.

Table 2

VCC VBB(V) 6.0 4.0 2.0 0.0

VC

C =

15V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

Vcc

= 1

2V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

VC

C =

9 V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

VC

C =

6 V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

VC

C =

4 V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

VC

C =

2 V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

VC

C =

0 V

VCE(V)

IC(mA)

VBE(V)

IB*(A)

DC*

9- Explain how the CE output characteristics (VCE, IC) would be affected by a

decrease in temperature.

10- Draw (IC vs. IB), and (VCE vs. IB) when VCC = 15 volt.


Exp. 6

Objectives

To investigate the bipolar junction transistor (BJT) applications as simple common-

emitter and common-collector AC amplifiers biased in the active mode and

switching device

Pre-Lab Assignments

Pre1. Simulate all the circuits in the experiment sheet; using the MultiSIM simulation

packages, to verify your results and graphs.

Pre2. Determine RB and RC for the transistor inverter of Figure 3, if: IC-sat > 3mA.

(Note that proper design for the inversion process requires the operating point

to be switched from cut-off to saturation region).

Hint: IC-Sat VCC / RC and IB-max IC-Sat / . (By choosing IB-max greater than the value derived from the above equation the

BJT is forced to switch to saturation region. The value of is the average of

in from the last experiment).

Theory

A typical integrated circuit (IC) and operational amplifier OP-AMP contains a large

number of transistors that perform many functions. The simplest way to analyze such

a circuit is to regard each individual transistor as a stage and to analyze the circuit as a

collection of single transistor stages. In this part of the experiment, you will examine

the behavior of some AC single-stage amplifiers with resistors supplying the bias

voltages and currents. In this experiment, two BJT amplifier configurations will be

investigated; the common-emitter, and the common-collector amplifier. Both

amplifiers typically use a self biasing circuit and have a relatively linear output. You

will also measure properties such as voltage gain Av.

• Common-Emitter Amplifier

The Common-Emitter (CE) amplifier is characterized by high voltage and current

gains, Av and Ai, respectively. The amplifier typically has a relatively high input

resistance Zi (1 to 10 k) and is generally used to drive medium to high resistance

loads. The circuit for the common-emitter used in applications where a small voltage

signal needs to be amplified to a large voltage signal. Since the amplifier cannot drive

low resistance loads RL, if the load RL is low, then usually it is cascaded with a

Common-Collector (CC) (some times called, emitter follower or buffer) circuit that

can act as a driver.

• Common-Collector (Emitter follower) Amplifier

The common-collector amplifier (emitter-follower), is a unity voltage gain Av and a

high current gain Ai amplifier. The input resistance Zi for this type of amplifiers is

BJT ac Amplifier & Switch


Vin

VO

RC

SW

VCC

(a)

Q1

BJT

RC

VCC

RB Vin

VO

(b)

usually (1 to 10 k). Because the amplifier has unity voltage gain (Av 1), it is

useful as a buffer amplifier providing isolation between two circuits while providing

driving capability for low resistance loads.

• BJT Switching Device

The basic element of logic circuits is the transistor switch. In an electronic circuit,

mechanical switches are not used. Transistors can be used as simple electronic

switches or logic gates. A schematic of such a switch mechanically and electronically

is shown in Figure 1.

When Vin = 0.0; is in low state, the BJT switch is OPEN; the transistor is OFF (in

cut-off region), IC = 0.0; providing a constant voltage at collector to emitter, VO = VCE

= VCC (open switch).

When Vin is in high state, the BJT switch is CLOSED, IC = (VCC - VCE-sat) / RC, the

transistor is saturated (in saturation region) (i.e. closed switch) providing a small yet

constant voltage at collector to emitter, VCE-sat 0.2V 0.0 V.

Figure 1

The above BJT circuit is also called an "inverter" or a "NOT" logic gate. Let's

assume that the low state is at 0.2 V and the high state is at 5 V, where VCC = 5 V.

When the input voltage Vin is low ( 0.0 < Vin < VTh ), BJT will be in cut-off region,

and VO = VCC = 5 V (high state). When input voltage Vin is high (Vin >> VTh), with

proper choice of RB, BJT will be in saturation, and VO = VCE-Sat 0.2 V (low state).



1- Oscilloscope . 2- Function Generator (FG)


5- Project Breadboard. 6- Resistors of 100,220,2x1K,10K, 470K.

7- Capacitors of 2.2µF. 8- BC107 BJT .

9- Connection Wires and coaxial cables Probes.

Procedure

PARTA: BJT AC Amplifier

A1 Common-Emitter Amplifier

1- Construct the circuit shown in Figure 2, using BC107 BJT. Use the VCC=+15V

from the project breadboard power supply. (Make sure the BJT is connected with

the correct leads). Do not connect the Oscilloscope and the Function Generator at

this stage.

2- Set the correct setting of the DMM to measure amplifier’s Q-point. Do not apply

any Vs from Function Generator, just apply VCC and measure VCEQ, VBE, ICQ and

IBQ quiescent DC values. Also calculate the DC current gain DC , VRB2 then fill

data in Table 1. ( Hint: ICQ (VCC – VCE) / (RC + RE), and IBQ = VRB2 / RB2 )

Table 1.

VCC

(V) VCEQ

(V) VRB2

(V) IBQ

(mA) ICQ

(mA) VBE

(V) DC

15

3- Connect the Function Generator and the Oscilloscope to the circuit as shown in

Figure 2, use 1:10 probe for CH1.

4- Switch ON the Oscilloscope and the Function Generator and set the source voltage

Vs to sinusoidal signal, 100mVPP, 2kHz. (Note: set the input coupling switch of the

Oscilloscope to the AC coupling mode).

5- Using the Oscilloscope, measure the small-signal voltage gains, Av1 =Vo /Vs and

Av2 = Vo / Vin (for Av2, connect the high terminal of CH1 probe to the base at point

B).

6- Sketch the Oscilloscope screens on the respective grids in Table 2.

7-Gradually increase the source signal Vs amplitude and determine the onset of

clipping at the output. Draw the signal on Table 2.

8-When finished, set the source voltage Vs to 100mVPP.


RC

RB2

vs =100mVPP

Q1 BC107

H2

L2

H H1

L1 L fin = 2 kHz

VCC=+15V

RE

10k

RB1 1k 470k

100

CS 2.2F

B

C

E

vo

vin

Figure 2

Table 2

Vs and Vo signals Vin and Vo signals

Av1 = ……………..…… Av2 = ………………..……

Vs and Vo clipped signals

.

Av = ………………..……

9-From the above data check VBE and VBC to verify that the transistor is in its forward

action region of operation. Why is VCE 7.5 V a good choice?

10-From the above data. What is the relationship between Av2 and Av1? Explain.

11-What is the value of rл?


A2: Common-Collector (Emitter follower) Amplifier

1- On the same circuit of Figure 2, connect the high terminal of the Ch2 probe to

emitter at point E.

2- Repeat steps 5 to 7 in part A-1 without measuring Av2. Sketch the Oscilloscope

screens on the respective grids in Table 3.

3- When finished, set the source voltages to 0.0. Then switch off the supplies and

disconnect the circuit.

4- Compare between the two types of amplifiers in terms of Av, Zi, Zo and φ.

Table.3

Vs and Vo signals. Vs and Vo clipped signals..

Av1 = ………………..……

Av=………………..……

PART-B DC Test of the BJT Switching Device

1- Construct the circuit shown in Figure 3. By using BC107 BJT. Use the VCC=+5V

from the project breadboard power supply, RC= 1kΩ and RB =4.7kΩ. (Make sure

the BJT is connected with the correct leads).

2- Set the DC supply output adjustment potentiometers fully counter clock wise, then

switch it ON.

3- Vary the input voltage Vin according to Table 4. Use the DMM to measure the

output voltage VO and record it in Table 4.

4- When finished, set the Vin to 0.0V, then switch OFF and disconnect the power

supply only.

5- Explain what happens to VO and why.

6- Calculate the value of Vin-min, for which the BJT will

start to enter the saturation region. Verify your

calculation experimentally.

7- Sketch the VO vs. Vin.

RB = 4.7k

RC = 1k

Vin (V) VO (V) IC (mA)

0.0

3.0

5.0


Figure 3

Table 4

Metal Oxide Semiconductor Field Effect Transistor

( MOSFET )

Exp. 7

Objectives

• To identify the leads of the Metal Oxide Semiconductor Field Effect Transistors

(MOSFET) by using the DMM and data sheet.

• To investigate the DC behavior and the characteristics of a MOSFET in several

regions of operation.

• To determine small signal parameter gm .

• To investigate the MOSFET applications as simple common-source and common-

drain AC amplifiers.

Pre-Lab Assignment

Pre1. By using the data sheet of the ZVN2110A MOSFET, look up to the following:

o Zero-Gate Voltage Drain Current IDSS (min) ____mA. IDSS (max) ___ mA.

o Maximum rated continuous drain current ID (max) ______ mA .

o Gate-source threshold voltage VGS(th) ____ V .

o Static Drain-Source On-Resistance RDS(ON) ______ .

o Total maximum power dissipation PD _____ mW .

Pre2. Simulate all the circuits in the experiment handout using the MultiSIM

simulation packages, to verify your results and graphs.

Pre3. What is the primary difference between a MOSFET and a BJT ?

Theory

The Metal Oxide Semiconductor Field Effect Transistor (MOSFET), is a device used

to amplify or switch electronic signals. The MOSFET includes a channel of n-type or

p-type semiconductor material, and is accordingly called an NMOSFET or a

PMOSFET (also commonly nMOS, pMOS). It is by far the most common transistor

in both digital and analog circuits, though the bipolar junction transistor was at one

time much more common.

A variety of symbols are used for the MOSFET as shown in Figure 1. Sometimes

three line segments are used for enhancement mode and a solid line for depletion

mode. Another line is drawn parallel to the channel for the gate.


P-channel

N-channel

MOSFET enh MOSFET enh MOSFET dep

Figure 1

Mode of Operation

The operation of a MOSFET can be separated into three different modes, depending

on the voltages at the terminals. For an enhancement mode, n-channel MOSFET,

the three operational modes are:

1-Cutoff mode when VGS < Vth

Where Vth is the threshold voltage of the device. According to the basic threshold

model, the transistor is turned off, and there is no conduction between drain and

source.

2- Triode mode or non saturation mode when VGS > Vth and VDS < ( VGS - Vth )

The transistor is turned on, and a channel has been created which allows current to

flow between the drain and the source. The MOSFET operates like a resistor,

controlled by the gate voltage relative to both the source and drain voltages.

3- Saturation or active mode when VGS > Vth and VDS > ( VGS - Vth )

The drain current is now weakly dependent upon drain voltage, and controlled

primarily by the gate source voltage

The DC behavior of a MOSFET is specified most completely by the output

characteristics, ID vs. VDS, with VGS as a parameter, and the input-output

characteristic, ID vs. VGS.

MOSFET drain current vs. drain-to-source voltage for several values of (VGS − Vth);

the boundary between linear (Ohmic) and saturation (active) modes is indicated by

the upward curving parabola.

• MOSFET AC Amplifier Device

Two of the most popular configurations of small-signal MOSFET amplifiers are the

common source (CS) and common drain (CD) configurations.



1- Oscilloscope. 2- Function Generator (FG)


5- Project Breadboard. 6- Resistors of 1K, 220K, 470, 100, 120K.

7- Capacitor of 1, 10µF. 8- ZVN2110A MOSFET or equivalent.

9- Connection Wires and Coaxial Cables.

The common source and common drain amplifiers, like all MOSFET amplifiers, have

the characteristic of high input impedance. The value of the input impedance for both

amplifiers is basically limited only by the biasing resistors RG1 and RG2 as shown in

Figure 2. Values of RG1 and RG2 are usually chosen as high as possible to keep the

input impedance high. High input impedance is desirable to keep the amplifier from

loading the signal source. One popular biasing scheme for the CS and CD

configurations consists of the voltage divider RG1 and RG2. This voltage divider

supplies the MOSFET gate with a constant DC voltage. This is very similar to the

BJT biasing arrangement. The main difference with the BJT biasing scheme is that

ideally no current flows from the voltage divider into the MOSFET.

The CS and CD MOSFET amplifiers can be compared to the CE and CC BJT

amplifiers respectively. Like the CE amplifier, the CS amplifier has negative voltage

gain and output impedance approximately equal to the drain resistor (collector resistor

for the CE amplifier). The CD amplifier is comparable to the CC amplifier with the

characteristics of high input impedance, low output impedance, and less than unity

voltage gain.

Procedure

Part-A MOSFET Lead Identifications by using the DMM

1- Use the data sheet to find the pin out of the MOSFET.

2- Check out that the used MOSFET is working properly using DMM, turn on the

DMM and set it to ( ). Plug a black test lead into the Common (−) 4mm banana

socket, and a red test lead into the V (+) 4mm banana socket of the DMM.

Connect the black test lead into the V (+) 4mm banana socket of the DMM.

3- Connect one lead of the DMM to the Drain (D) pin and the other lead of the DMM

to the Gate (G) pin. Check the reading of the DMM. Explain your result.

4- Connect the one lead of the DMM to the Source (S) pin and the other lead of the

DMM to the Gate (G) pin. Check the reading of the DMM. Explain your result.

5- Connect the one lead of the DMM to the Source (S) pin and the other lead of the

DMM to the Drain (D) pin. Check the reading of the DMM. Explain your result.

Part-B Current-Voltage Characteristics of a CS MOSFET

B-1 : ID versus VGS Characteristic

1- Construct the circuit shown in Figure 2. By using the ZVN2110A MOSFET.

(Make sure the transistor is connected with the correct leads as shown in Figure 1).

2- Set the DC power supplies output adjustment potentiometers fully counter clock

wise, then switch ON the supplies.

3- Adjust the DC power supply of VDD = +12 volt.


Note

The value of the Gate current IG is equal to zero, so VGS = VGG

4- Adjust the VGG power supply to obtain the values according to Table 1.

5- Use the DMM to measure the values of ID, and then record the readings in Table 1.

6- When finished, set the VGG and VDD to 0.0V. Then switch OFF the DC power

supplies.

7- From the results in Table 1, what is the value of threshold voltage VGS(th) ?

8- From your data in Table 1, plot the experimental output drain characteristics (ID vs.

VGS), and determine VGS(th) on the plot.

9- From the experimental results calculate the average transconductance gm. For what

significant reasons is the experimental gm different from the manufacturer's

specified value?

B-2 : ID versus VDS Characteristic


2- Set the DC power supplies output adjustment potentiometers fully counter clock

wise, then switch ON the supplies.

3- Adjust the DC power supply of VDD according to Table 2.

4- Adjust the VGG power supply to obtain the values according to Table 2.

5- Use the DMM to measure the values of VDS and ID, and then record the readings in

Table 2.

6- Repeat steps 3 and 5 for all values of VGG and VDD.

7- When finished, set the VGG and VDD to 0.0V. Then switch OFF the DC power

supplies.

VGG (V) 0.0 1 1.2 1.3 1.4 2 3

ID (mA)

Table 1


Figure 2

8- From your data in Table 2, plot the experimental output drain characteristics (ID vs.

VDS), draw the load line, determine the regions of operations, and determine the Q-

point (operating point).

9- Explain qualitatively how the CS input characteristics would be affected by a

decrease and increase in temperature.

PART-C MOSFET AC Amplifier Device

C-1 Common-Source Amplifier with Source Resistor (RS)

1- Construct the circuit shown in Figure 4, Use VDD = +12V from the project

breadboard power supply.

Do not connect the Oscilloscope and the Function Generator at this stage.

2- Set the correct setting of the DMM to measure amplifier’s Q-point. Do not apply

any Vs from Function Generator, just apply VDD then measure VDSQ, IDQ and

VGSQ quiescent DC values. Record the measured values in Table 3.

3- Connect the Function Generator and the Oscilloscope to the circuit as shown in

Figure 4.

Table 3

VDD (V) VDSQ (V) VGSQ (V) IDQ (mA)

12

VDD VGG(V) 7 4

12V ID (mA)

VDS (V)

9 V ID (mA)

VDS (V)

6 V ID (mA)

VDS (V)

3 V ID (mA)

VDS (V)

0 V ID (mA)

VDS (V)


Figure 4

Table 2

Figure 3

4- Switch ON the Oscilloscope and the Function

Generator and set the source voltage Vs to sinusoidal

signal, 100mVPP, 5kHz. (Note: set the input coupling

switch of the Oscilloscope to the AC coupling mode).

5- Using the Oscilloscope, measure the small-signal

voltage gain, Av = Vo / Vs. Sketch the Oscilloscope

screens on the respective grid.

6- When finished, set the source voltage Vs to 100mVPP.

7- Note the phase shift between output and input

voltages. Is the amplifier inverting or non-inverting?

C-2 Common-Source Amplifier without Source Resistor (RS)

1- Starting again with the same circuit shown in Figure 4,

add 10μF in parallel with the Source resistance (RS).

2- Connect channel 2 of the Oscilloscope to the Drain

(D).



screens on the respective grid.

4- What happen to the Voltage Gain when adding the

capacitor parallel to RS? Explain the effect of RS.

C-3 Common-Drain (Sourse-Follower) Amplifier

1- On the same circuit of Figure 4, connect the high

terminal of Ch2 probe to Source (S) and remove

10μF in parallel with the Source resistance (RS).



screens on the respective grids in Table 6.

3- When finished, set the source voltages to 0.0V. Then

switch off the supplies and disconnect the circuit.

4- Note the phase shift between output and input

voltages. Is the amplifier inverting or non-inverting?

5- Compare between the CS and CD amplifiers in terms of Av, φ.


Objectives

• To investigate the AC behavior of the frequency and phase response of a BJT.

• To measure upper and lower cutoff frequencies of a CE amplifier.

Figure 1


1- Oscilloscope 2- Function Generator (FG)


5- Project Breadboard. 6- 680,820, 2x(1, 2.2, 3.3,10) kΩ.

7- Capacitor of 1µF, 2.2µF, 22µF. 8- BC107 BJT

9- Connection Wires and coaxial cables.

Pre-Lab Assignment

Simulate all the circuits in the experiment handout using the MultiSIM simulation

packages, to verify your results and graphs.

Procedure

Part A: Frequency response of a BJT Common Emitter amplifier

1- Construct the circuit shown in Figure 1 by using BC107 transistor. (Don’t connect

the Load Resistor RL.)

2- Switch ON the Oscilloscope and the Function Generator. Set the source voltage

(VS) to 50mVpp sinusoidal.

BJT Frequency Response Amplifier

Exp. 8



4- Vary the input signal frequency according to Table 1. measure the value of Vo,

calculate the value of voltage gain Av and the phase shift ( )between the input

and the output signals.


Table 1

f (Hz) Vs (VP) Vo (VP) Av (V/V) Phase Shift

100

500

1K

5K

10K

20K

50K

100K

200K

500K

1M

6- According to the data filled in Table 1, determine the midrange, Lower corner and

the Upper corner frequencies and fill them in Table 2 below.

7- What is the value of the phase shift at the midrange frequencies? What does that

mean?

8- What is the relation between the voltage at the midrange and the voltage at the

lower and the upper frequencies?

9- Draw the Frequency Response of a Common Emitter Amplifier.

Table 2

Critical

Points f (Hz) Vs (VP) Vo (VP) Av (V/V)

Phase Shift

Mid Range

Lower Corner

Upper Corner


Part B: Frequency response of a BJT CE Loaded amplifier

1- Leave the connection of the circuit shown in Figure 1 and connect the load resistor

RL.

2- Change the value of the input signal frequency according to Table 1, and

determine the midrange, the lower and the upper frequencies then fill the data in

Table 3.

Table 3

Critical

Points f (Hz) Vs (VP) Vo (VP) Av (V/V)

Phase Shift

Mid Range

Lower Corner

Upper Corner

3- What happen when we add a load resistor to the common emitter amplifier?

Explain.


Objectives

• To gain experience with Operational Amplifier.

• To study the use of Op.Amp. as an inverting amplifier, integrator, Adder, Non inverting

(Op.Amp) and comparator.

• To study use of the OP amp as a Precision Rectifier and Square wave Oscillator.


1- Oscilloscope (Scope / CRO). 2- Function Generator (FG) or Signal Generator.

3- Digital Multimeter (DMM). 4- DC power supply.

5- Bread-board. 6- 3 X 10K, 1K, 2X 15K , 1µF and 0.1µF.

7- Connection Wires and Coaxial Cables. 8- Op-Amp 741

Pre-Lab Assignments Build the circuit used in this Experiment using the MultiSIM simulation package to

verify your results and get the graphs.

Theory

The operational amplifier is an extremely efficient and versatile device. Its

applications span the broad electronic industry filling requirements for signal

conditioning, special transfer functions, analog instrumentation, analog computation,

and special systems design. The analog assets of simplicity and precision characterize

circuits utilizing operational amplifiers.

The precision and flexibility of the operational amplifier is a direct result of the use of

negative feedback. Generally speaking, amplifiers employing feedback will have

superior operating characteristics at a sacrifice of gain.

Procedure

Part A: Inverting amplifier

1- Construct the Op.Amp circuit as shown in Figure 1.

2- Vary VS to get the value of Vin as shown in Table 1, measure Vo and fill them in

Table 1.

3- Plot Vo(t) curve and Vs(t) curves.

4- What is the equation of the output voltage related to the input signal and calculate

the voltage gain (Av)?

5- What is the phase shift between the input and the output signals?

Operational Amplifier Application

Exp. 9


Table 1

Vin(mV) 15 30 45 100 150 200 250 300 350 400

Vo (V)

6- Where does the Op-amp 741 saturate? What is the

value of the VO-Sat?

7- Remove the DC supply and replace it by A.C supply.

8- Adjust the input signal to 0.1Vp-p and 1 kHz.

9- Connect CH1 to Vin and CH2 of the Oscilloscope to

the output of the op-amp. Sketch Vo (t) and calculate

voltage gain Av.

Part B: Non - Inverting amplifier

1- Construct the Op-Amp circuit as shown in the Figure 2.

2- Set the source voltage Vs to 0.1 Vp-p, 1kHz.

3- Draw Vo(t) on the respective screen grids below, and measure peak voltage.

4- Write down the equation of the output related to the input signal and calculate the

voltage gain Av.

6- What is the phase shift between the input and the output signals?

Part C: Comparator

1- Refer to Figure 3, set Vref = 0 V, Vin =10Vp-p, 1 kHz.

2- Observe Vin(t) and Vo (t) on the Oscilloscope Channels.

3- Draw the signals appear on the Channels.

4- Set Vref = 2 V and draw the signals appear on the

channels.


5- What is the difference between the signals when Vref = 0 V and Vref = 2 V?

Part D: Integrator


2- Apply a square-wave signal at Vin with 500Hz frequency and 10 Vp-p.

3- Observe Vo(t) Signal on the Oscilloscope and draw the output signal on the

respective Oscilloscope screen.

4- Write down the Equation of the output related to the input signal.

Part E: Adder


2- Connect V1 to 1V( D.C supply)

3- Connect V2 to a Function Generator ( Sine wave 2Vp-p, 1kHz)

4- Connect the Oscilloscope CH1 to the input sine wave and channel 2 to the output

voltage, be sure to put CH2 coupling to D.C. Sketch the output signal on the

respective Oscilloscope screen below.

5- Repeat steps ( 2 - 4 ), replace V2 by 6Vp-p,1kHz. Explain what happen


Vref=0 V Vref=2 V

Figure 5

Part F: Precision Rectifier


2- Apply a sine wave signal at the input with 400mVp-p, 2kHz.

3- Connect CH2 of the Oscilloscope to the Output of the Op-amp.

4- Draw the output signal on the respective Oscilloscope screen below and measure

the output peak voltage.

5- What is the main difference between the rectifiered signals if we use Op-amp

instead of using diode only as in Exp1?

Part G: Square Wave Oscillator


2- Connect CH2 of the Oscilloscope to the Output of the Op-amp and draw the output

signal on the respective Oscilloscope screen below.

3- What is the frequency of the output signal?

Note: the period of the output signal (T) is given by the following Equation:

1

1ln2RCT

21

1

RR

R

4- Explain how can we change the frequency of the output signal?


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